1. Field of the Invention
The present invention relates to an improved apparatus for treating the surface of a body to produce a surface treated material which can be suitably used as a constituting member for electric devices, electron devices, or especially as a substrate for the light receiving member for electrophotography.
2. Description of the Prior Art
Metallic plates, metallic cylinders and metallic endless belts for use as substrates for light receiving members, such as electrophotographic photosensitive members, are required to have a surface morphology suitable for use purposes. Accordingly, the surfaces of such metallic substrates are finished by various machining processes or grinding processes. Aluminum alloy substrates are used generally as most suitable substrates. The surface of an aluminum alloy substrate is processed and finished in a desired surface morphology and a desired light receiving layer is formed over the surface thus finished.
However, these conventional surface finishing methods, i.e., machining and grinding, sometimes form intermetallic compounds of Si/Al/Fe system or Fe/Al system, TiB.sub.2, or oxides of Al, Mg, Ti, Si and/or Fe in the structure of alloys, form voids of H.sub.2 or form surface discontinuity such as grain boundary fracture.
In any case, when an aluminum alloy material is used as the substrate, its surface is made so as to have extremely high cleanliness. However, the surface of such an aluminum alloy material is active even in an ultra-high vacuum of 10.sup.-9 mmHg, and hence an oxide film of a thickness on the order of 30 Angstrom is likely to form on the surface of such an aluminum alloy material even in such an ultra-high vacuum.
Owing to such a problem, a substrate surface-finished by the conventional cutting method or grinding method causes various problems and defects in light receiving members fabricated by using such a substrate. Particularly in the case of an electrophotographic photosensitive member fabricated using such a substrate, the light receiving layer formed on the substrate often becomes unsatisfactory in evenness and homogeneity, and to lack uniformity in electrical, optical and/or photoconductive characteristics entailing defects in images obtained and, sometimes, such an electrophotographic photosensitive member is incapable of practical application. Such problems are particularly conspicuous when the light receiving layer is formed of a non-single-crystal material containing silicon atoms as the matrix.